Pore pressure prediction while drilling: Three-dimensional earth model in the Gulf of Mexico

ABSTRACT:

Subsalt Gulf of Mexico deep-water wells routinely cost in excess of $100 million. A reliable pore pressure prediction can translate into considerable savings in terms of drilling costs and safety. Traditional methods used to determine pore pressure are based on either logs (e.g., Eaton’s or Bowers’ methods) or seismic data (e.g., calibrated seismic velocities, acoustic impedance). Another method for pore pressure prediction is based on basin modeling: building a three-dimensional earth model and simulating the processes of pressure formation, through geologic time. Recent advancements in basin modeling, such as the coupling of stress and pressure and the implementation of models for mineral diagenesis and rock failure, have significantly improved its applicability. However, no single method is commonly accepted as better than another, therefore, using, comparing, and integrating all three methods together in a predrilling project can provide a higher degree of confidence for pore pressure prediction. The purpose of this presentation is to describe a new approach to pore pressure prediction that combines the above methods with petroleum system modeling. A special emphasis is put on the explanation of the basin modeling workflow. The first step of the workflow is to create and calibrate a regional model based on a set of regional maps with the main goal of providing the regional context. The second step is to create a smaller area of interest (AOI) model using high-resolution structural and facies maps. This refined model is then used for pore pressure prediction at the prospect scale. The smaller AOI model, albeit at very high resolution, allows a model to be run overnight, so that pore pressure can be predicted ahead of the drilling bit. Finally, the predicted pore pressure and fracture gradient allow the drilling engineer to optimize well performance and reduce drilling costs.

BIOGRAPHY:

Fausto Mosca, a world-renowned basin modeler and petroleum geochemist, has joined Stratum Reservoir’s OilTracers® Group. The OilTracers® consulting team specializes in integrating geochemical, geological, and engineering data to solve complex challenges throughout the field life cycle.

Fausto is a master user of PetroMod (1D, 2D, 3D, TecLink 2D, and Stress Simulator), Trinity T3, and Genesis 1D, and is widely recognized for his leadership in basin modeling in complex thrust belt and salt tectonic settings. He brings extensive expertise in solving exploration, development, and production challenges through advanced organic geochemical analysis of gases, oils, and source rocks.

He is also a recognized expert in pore pressure prediction while drilling and in the real-time interpretation of Gas While Drilling (GWD) data generated by advanced mud logging tools.

Throughout his career, Fausto has served as a subject-matter expert with Agip, Shell, Devon, Nexen, and Murphy, working across nearly all major sedimentary basins worldwide, including Europe and the Mediterranean, the USA and Mexico, North, Central, West, and South Africa, Central America, South America (Pacific and Atlantic margins), Far East Asia, and Australia.